Greg Reynolds and Casey Weathers, the Rockies’ No. 1 draft choices in 2006 and ’07, have seen their careers derailed by major arm problems. So the last thing the Rockies need is for Christian Friedrich, their top pick in 2008, to fall victim to injuries.

Friedrich, a left-hander out of Eastern Kentucky, dominated hitters in his first two pro seasons, allowing 139 hits and striking out 224 in 167 2/3 innings. But things changed in a hurry last season when Friedrich reached Double A Tulsa.

He was shut down twice during the season, first with elbow tendinitis and later after taking a nasty one-hopper off the same elbow, before being shut down for good with almost a month left in the season. His bottom line for 2010: 3-6, 5.05 in 18 starts, with 78 strikeouts and 100 hits allowed in 87 1/3 innings.

“I wanted to just stay healthy and get over the 100 (innings) mark without any worries,’’ said Friedrich.

And this year? Friedrich, like so many other young pitchers, needs to cross a threshold and prove he can get hitters out and be durable enough to pile up significant innings.

“It’s throwing more strikes, attacking hitters,’’ he said. “As fun as strikeouts are, I had a lot more fun last year when I had double-digit ground balls that translated into me being in the game in the seventh inning.

“Being efficient and attacking hitters. That’s the mode I want to be in this year. If I walk out of here healthy, everything will take care of itself.’’